Data from: Attracting mutualists and antagonists: plant trait variation explains the distribution of specialist floral herbivores and pollinators on crops and wild gourds

PREMISE OF THE STUDY: Floral traits play important roles in pollinator
attraction and defense against floral herbivory. However, plants may
experience trade-offs between conspicuousness to pollinators and herbivore
attraction. Comparative studies provide an excellent framework to examine
the role of multiple traits shaping mutualist and antagonist interactions.
METHODS: To assess whether putative defensive and attractive traits
predict species interactions, we grew 20 different Cucurbitaceae species
and varieties in the field to measure interactions with pollinators and
herbivores and in the greenhouse to assess trait variation. Cucurbits are
characterized by the production of cucurbitacins, bitter nonvolatile
terpenoids that are effective against generalist herbivores but can
attract specialist beetles. We determined whether plant traits such as
cucurbitacins predict herbivore resistance and pollinator attraction using
an information-theoretic approach. KEY RESULTS: Mutualists and floral
antagonists were attracted to the same cucurbit varieties once they
flowered. However, rather than cucurbitacin concentration, we found that
the size of the flower and volatile emissions of floral sesquiterpenoids
explained both pollinator and floral herbivore visitation preference
across cucurbit taxa. This pattern held across cucurbit taxa and within
the Cucurbita genus. CONCLUSIONS: Surprisingly, floral sesquiterpenoid
volatiles, which are associated with direct defense, indirect defense, and
attraction, rather than defense traits such as cucurbitacins, appeared to
drive interactions with both pollinators and floral herbivores across
cucurbit taxa. Identifying the relevant plant traits for attraction and
deterrence is important in this economically valuable crop, particularly
if pollinators and floral herbivores use the same plant traits as cues.